求助！PREP1-24

gabriel_djh

24.

Tiger beetles are such fast runners that they can capture virtually any nonflying insect.However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack.Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

(A) When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.

(B) In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.

(C) The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.

(D) If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.

(E) When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.


正确选项为C。为什么选项E不对啊？还有帮忙解释一下正确选项C,谢谢谢谢了！

gabriel_djh

这样一说我明白了~~~~~~~~~~~~~

quellekind

我觉得C是反对hypo1，支持hypo2。反对hypo1是因为常理是追得快则累则追击时间短，如

果不管追得快还是慢，追的时间是一样的那说明pause和rest无关。而the beetle increases

its speed after its next pause说明这个beetles是在停下后才加速的，说明它需要停下看

清prey提速了才判断是要加速，支持hypo2。
B是反对两者。首先反对hypo2很清楚因为beetles对变化反应快。然后反对hypo1是因为常理是

上坡容易累要多休息而下坡反之，但是这个beetles上下坡pause频率一样，说明pause和rest

无关。
E能支持hypo2，但不能weaken hypo1。
这道题需要太多常识，题目出的很不好，但考着了也没招。

kzang90

(B) In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction,削弱2 and pause equally frequently whether the chase is up or down an incline.因为能以平均的频率来pause,我感觉是支持了1，跑跑累了歇歇跑跑累了歇歇。。。。。谁帮我解释一下B好吗？

onedayling

请问。。。这道题是不是B两个都加强了？

gabriel_djh

我再仔细想想吧！谢谢了！

greates

这道题的关键是需要找到一个实验，满足在支持某假设的时候还能够同时削弱另一个假设。

hypothesis 1: 间歇性休息室因为无法维持高速运动太久。
   to undermine: 发现运动更久也没问题。
hypothesis 2: 是因为高速运动时无法处理快速变化的目标视觉图像，因此需要停下来再次确认目标位置。
   to undermine: 1)在目标没有变化时也需要停下来，比如目标为静止状态；2)目标有快速的移动时，也没有停下来。

C)选项可以加强假设1，同时削弱假设2。因为如果假设2成立，那么当insect从静止开始移动会导致tiger beetles的moving interval被影响，比如缩短当前的interval停下来重新确认目标位置。这个也加强了假设1，因为证明了外界条件改变不会导致一次飞行时间变长。

E)至少无法加强或者削弱假设1，也无法说一定能够加强假设2，因为这反应有可能是因为假设2，也有可能只是表明了tiger beetles在一次短跑中不能转弯而已。